초록
In order to clarify the influence of various factors on the motion of a fiber in non-Newtonian viscoelastic fluids, the free frilling behavior of a cylindrical slender body has been experimentally investigated in stationary polymer solutions. In this paper, experimental results on the effects of initial angle, fluid flow property, and body density on the frilling trajectory, horizontal and vertical velocities, and variation of attitude off slender body were reported in detail. Furthermore, the hydrodynamic mechanism of the results was discussed by considering the rheological properties of polymer solutions and introducing a quid boundary layer theory. Main findings obtained firm this study can be summarized as follows (1) The initial angle inonces the flee frilling behavior of a slender body only in the small region where the body starts its motion. Beyond this region the motion of a body is independent of the initial use. (2) Both the horizontal and vertical velocities of a body become smaller for the more concentrated polymer solutions. In addition, the final orientation angle of a body becomes closer to vertical direction as the solution concentration increases. (3) With increasing the body density, translational velocities of a body become larger but the final orientation an인e remains unchanged. (4) Falling behavior of a slender body can be inteivreted by a new mechanism introducing the competition between inertia and viscoelastic effects as well as a supercritical flow theory around a body.
